What is the difference between smalldatetime and datetime?

	DateTime	SmallDateTime
Storage Size	8 Bytes	4 Bytes
FORMAT	YYYY-MM-DD hh:mm:ss.nnn	YYYY-MM-DD hh:mm:ss
MIN Value	1753-01-01 00:00:00	1900-01-01 00:00:00
MAX Value	9999-12-31 23:59:59.997	2079-06-06 23:59:00
Accuracy	Rounded to increments of .000, .003, or .007 second It means: If time part in the date is 23:59:58.990 or 23:59:58.991, it will be stored as 23:59:58.990.	1 Minute Second’s values that are 29.998 seconds or less are rounded down to the nearest minute. And second’s values of 29.999 seconds or more are rounded up to the nearest minute. So seconds part value is always 00.